Umm.. how did the coin move towards the left without any input of energy? If the treadmill was going at a constant speed even with the most ideal conditions, the coin would move to the right because of friction and loss of energy.

PsyLord:Umm.. how did the coin move towards the left without any input of energy? If the treadmill was going at a constant speed even with the most ideal conditions, the coin would move to the right because of friction and loss of energy.

Notice that the bookshelf in the background doesn't look quite level? The treadmill isn't flat. If you set the incline on the treadmill just right, theoretically the slight increase in speed from gravity should match the slight decrease in speed from friction.

And as far as the coin sometimes moving left, sometimes right: The motors in treadmills aren't perfectly consistent.

KickahaOta:PsyLord: Umm.. how did the coin move towards the left without any input of energy? If the treadmill was going at a constant speed even with the most ideal conditions, the coin would move to the right because of friction and loss of energy.

Notice that the bookshelf in the background doesn't look quite level? The treadmill isn't flat. If you set the incline on the treadmill just right, theoretically the slight increase in speed from gravity should match the slight decrease in speed from friction.

And as far as the coin sometimes moving left, sometimes right: The motors in treadmills aren't perfectly consistent.

Theoretically, you would then be able to do this with anything smooth and circular, like a marble or ball, or even a can of tuna. But you can't.

I'm going with someone adjusting the speed for the back and forth motion, and air to keep it from rolling off the sides.

KickahaOta:PsyLord: Umm.. how did the coin move towards the left without any input of energy? If the treadmill was going at a constant speed even with the most ideal conditions, the coin would move to the right because of friction and loss of energy.

Notice that the bookshelf in the background doesn't look quite level? The treadmill isn't flat. If you set the incline on the treadmill just right, theoretically the slight increase in speed from gravity should match the slight decrease in speed from friction.

And as far as the coin sometimes moving left, sometimes right: The motors in treadmills aren't perfectly consistent.

The motors? Really?What about the a/c frequency input from the power company???

The moving tread is far from a perfect flat plane.The odds of the same two points on the tread and coin connecting more than once are astronomical.

It is just a disc rolling down a long, flat enough, fake hill.The centrifugal force of the disc spinning keeps it upright.